JP5402520B2 - Method for producing ZnO vapor deposition material - Google Patents

Description

  The present invention relates to a transparent conductive film used for, for example, a solar cell, a liquid crystal display device, an electroluminescence display device, a transparent electrode of a transparent piezoelectric sensor of a touch panel device, an active matrix driving device constituting the display device, and an antistatic conductive film The present invention relates to a method for producing a ZnO vapor deposition material used for forming a conductive film used in coatings, gas sensors, electromagnetic shielding panels, piezoelectric devices, photoelectric conversion devices, light-emitting devices, thin-film secondary batteries, and the like.

  In recent years, a transparent conductive film is indispensable when manufacturing photoelectric conversion devices such as solar cells. An ITO film (indium oxide film doped with tin) is known as a conventional transparent conductive film. The ITO film has the advantages of excellent transparency and low resistance.

  On the other hand, cost reduction is required for solar cells, liquid crystal display devices, and the like. However, since indium is expensive, when an ITO film is used as a transparent conductive film, the solar cell inevitably becomes expensive. In addition, when manufacturing solar cells or the like, amorphous silicon is deposited on the transparent conductive film by plasma CVD. At that time, if the transparent conductive film is an ITO film, There was also a problem that the ITO film deteriorated by the hydrogen plasma.

  In order to eliminate these points, zinc oxide doped with conductive active elements such as Al, B, Si, Ge, Sc, Y, La, Ce, Pr, Nd, Pm, and Sm can be manufactured at a lower cost. It has been proposed to use a system film as a transparent conductive film for solar cells or the like, and a zinc oxide-based vapor deposition material for forming this zinc oxide-based film by vapor deposition has been disclosed (for example, see Patent Document 1).

JP 2008-088544 A (Claim 1, specifications [0005] to [0008])

  As shown in FIG. 6, the ZnO vapor deposition material disclosed in Patent Document 1 is obtained by mixing a ZnO powder 1 and an additive powder 2 for improving conductivity to obtain a raw material mixed powder 3, and from this powder, a compact is formed. After obtaining 5, a sintered body 6 to be a ZnO vapor deposition material is produced. If the mixing of the ZnO powder 1 and the additive powder 2 for improving conductivity is insufficient, the additive 2 may segregate, and the aggregate 4 of the additive powder is present in a small ratio. In the sintered body 6 produced by using the raw material mixed powder 3 having such a non-uniform distribution of the additive powder, the additive is segregated in the sintered structure. Will do. When film formation is performed using the sintered body 6 having a non-uniform composition distribution as a deposition material such as electron beam vapor deposition or plasma vapor deposition, the film composition is not constant, making it difficult to control the composition of the film. There is also a problem that the concentration of the additive element in the film is lowered. Furthermore, if the additive segregates, evaporation becomes unstable and splash occurs. When splash occurs, the film structure becomes non-uniform, and the specific resistance of the film increases accordingly.

  An object of the present invention is to provide a method for producing a ZnO vapor deposition material excellent in composition uniformity by suppressing segregation of a rare earth element oxide powder containing one kind of rare earth element added to a ZnO raw material powder. Another object of the present invention is to provide a method for producing a ZnO vapor deposition material from which a ZnO film having a uniform film composition can be obtained.

According to a first aspect of the present invention, a granulated powder is produced from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, and the granulated powder is formed into a pellet, tablet or plate. This is an improvement of a method for producing a ZnO vapor deposition material containing 2 to 20% by mass of the rare earth element after sintering the compact. As shown in FIGS. 1 and 3, the characteristic configuration is that the rare earth element oxide powder contains one element selected from the group of rare earth elements, the ZnO powder 12, and the rare earth element oxide powder 13. And a step of preparing the first slurry 11 having a concentration of 20 to 90 mass% by mixing the dispersion medium 15 and the binder 16, and a thickness of 5 to 500 μm by the doctor blade method using the first slurry 11. A step of forming the first green sheet 18 and a first green single layer body 19 produced by cutting the first green sheet 18 or a plurality of green single layer bodies are laminated to produce the first green laminated body 20. A step of firing the first green single-layer body 19 or the first green laminated body 20 to produce a first hybrid fired body 21, and pulverizing the first hybrid fired body 21 to obtain an average particle size of 0. .1-10 a step of preparing a first hybrid powder 25 [mu] m, viewed including the step of producing a granulated powder 32 by the first hybrid powder 25, the number of stacked first green laminate is from 2 to 100 layers, the The thickness of one green laminate is 10 to 1000 μm .

According to a second aspect of the present invention, a granulated powder is prepared from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, and the granulated powder is formed into a pellet, tablet or plate. This is an improvement of a method for producing a ZnO vapor deposition material containing 2 to 20% by mass of the rare earth element after sintering the compact. As shown in FIGS. 2 and 3, the characteristic configuration is that the rare earth element oxide powder contains one element selected from the group of rare earth elements, the ZnO powder 12 and the rare earth element oxide powder 13. And a step of mixing the dispersion medium 15 and the binder 16 to prepare a first slurry 11a having a concentration of 20 to 90% by mass, and using the first slurry 11a, a thickness of 5 to 500 μm by a doctor blade method. A step of forming the first green sheet 18a, a step of preparing the second slurry 11b having a concentration of 20 to 90% by mass by mixing the ZnO powder 12, the dispersion medium 15, and the binder 16, and the second. A step of forming the second green sheet 18b having a thickness of 5 to 500 μm by the doctor blade method using the slurry 11b, and a first group formed by cutting the first green sheet 18a The step of laminating the lean single layer body 19a and the second green single layer body 19b produced by cutting the second green sheet 18b to produce the second green laminated body 29, and the second green laminated body 29 A step of firing to produce a second hybrid fired body 30, a step of grinding the second hybrid fired body 30 to produce a second composite powder 31 having an average particle size of 0.1 to 100 μm, and this second look including a step of preparing a granulated powder 32 by hybrid powder 31, the number of laminated second green laminate is from 2 to 100 layers, the thickness of the second green laminate is that it is 10~1000μm .

  The third aspect of the present invention is an invention based on the second aspect, and is a method for manufacturing a ZnO vapor deposition material 34 in which the thickness of the first green sheet 18a and the thickness of the second green sheet 18b are the same or different. .

  A fourth aspect of the present invention is the invention based on the first or second aspect, wherein one element selected from the rare earth element group is Sc, Y, La, Ce, Pr, Nd, Pm or It is a manufacturing method of the ZnO vapor deposition material 34 which is Sm.

A fifth aspect of the present invention is a method of forming a ZnO film by a vacuum film formation method using the ZnO vapor deposition material 34 manufactured by the method of the first to fourth aspects as a target material.

  According to the manufacturing method of the first aspect of the present invention, a ZnO vapor deposition material which is a ZnO sintered body with improved dispersibility of rare earth element oxides, suppressed segregation and excellent composition uniformity can be obtained. Furthermore, according to the manufacturing method of the second aspect of the present invention, when producing a ZnO sintered body having a very low concentration of rare earth elements, the rare earth elements can be effectively dispersed. Further, according to the manufacturing method of the third aspect of the present invention, the aggregate of rare earth element oxide in the raw material mixed powder is flattened into fine particles by firing and pulverizing, and the rare earth element oxide in the sintered body It has the effect of suppressing segregation. In addition, according to the manufacturing method of the fourth aspect of the present invention, there is an effect that the formed ZnO film has good conductivity over a wide temperature range. In particular, Ce can provide high conductivity. When the vapor deposition material according to the first to sixth aspects of the present invention is used, stable vapor deposition is possible, the film composition is uniform, there is little change in the film composition at the time of film formation, and the desired conductivity and visible light transmittance are achieved. A ZnO film is obtained. This material can be used not only for forming a transparent conductive film but also for forming a conductive film such as a gas sensor, an electromagnetic shielding panel, and a piezoelectric device.

In the manufacturing method of Embodiment 1 of this invention, it is a figure which shows to the grinding | pulverization process of a 1st hybrid baking body. In the manufacturing method of Embodiment 2 of this invention, it is a figure which shows to the grinding | pulverization process of a 2nd hybrid sintered body. It is a figure which shows from the granulation process of a 1st or 2nd hybrid powder to a sintering process in the manufacturing method of this invention Embodiment 1 or 2. FIG. It is a schematic diagram which shows the microscopic structure from raw material mixed powder to a sintered compact of Embodiment 1 of this invention. It is a schematic diagram which shows the microscopic structure from raw material mixed powder to a sintered compact of Embodiment 2 of this invention. It is a schematic diagram which shows the microscopic structure from the raw material mixed powder to a sintered compact in the conventional sintering method.

  Next, an embodiment for carrying out the present invention will be described with reference to the drawings.

A. First Embodiment <Preparation Step of First Slurry>
As shown in FIG. 1, first, a first slurry 11 for forming a first green sheet is prepared. A raw material mixed powder 14 of a ZnO powder 12 having a purity of 98% or more and a rare earth element oxide powder 13 having a purity of 98% or more is dispersed in a dispersion medium 15, and a binder 16 is added to and mixed with the first slurry 11. Is made. Preferably, ZnO powder having a purity of 99.9% and rare earth element oxide powder having a purity of 99.9% are used. The compounding ratio of the ZnO powder 12 and the rare earth element oxide powder 13 is a ratio including 2 to 20 mass% of rare earth elements, where the total mass of ZnO and rare earth element oxide in the ZnO vapor deposition material is 100 mass%. A preferable ratio of the rare earth element is 3 to 6% by mass. If the rare earth element is less than the lower limit, the concentration of the rare earth element necessary for improving the conductivity of the film cannot be secured, and if the upper limit is exceeded, basic performance as a ZnO conductive film cannot be obtained. .

  The average particle diameter of the ZnO powder 12 is preferably 0.1 to 5 μm. When the thickness is less than 0.1 μm, the aggregation of the powder is remarkable, and when it exceeds 5 μm, the effect of forming a pseudo solid solution with the rare earth element oxide cannot be obtained sufficiently. The average particle size of the rare earth element oxide powder 13 is preferably 0.1 to 3 μm. If the thickness is less than 0.1 μm, the agglomeration of the powder becomes remarkable, and if it exceeds 3 μm, the effect of forming a pseudo solid solution with ZnO cannot be obtained sufficiently. The average particle size of these powders was determined by laser diffraction / scattering method (microtrack method), using Nikkiso Co., Ltd. (FRA type), using hexametaphosphate Na as a dispersion medium, and measuring time for one second for 30 seconds. The values measured three times were averaged.

  Examples of the dispersion medium 15 include water or an organic solvent. Among these, water is preferable in terms of workability and environmental load. Examples of the binder 16 to be added include methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose ammonium, ethyl cellulose, and polyvinyl alcohol. Among these, the cellulose-based binder is water-soluble and is preferable in terms of workability and environmental load. The addition amount of the binder 16 is preferably 1 to 20% by mass when the first slurry 11 is 100% by mass. As for the density | concentration (mass of the powder with respect to the total mass) of the 1st slurry 11 to prepare, 20-90 mass% is preferable. If it is less than 20% by mass, the moldability is lowered, and if it exceeds 90% by mass, molding becomes difficult. This is because a viscosity suitable for molding is required. Further, a dispersant or a plasticizer may be added to the first slurry 11. As the dispersing device, an impeller type stirring mixer is mainly used, but a rotary mixer such as a ball mill may be used.

<First green sheet forming step>
As shown in FIG. 1, the 1st slurry 11 prepared by said method is loaded into a doctor blade apparatus, and the 1st green sheet 18 of predetermined thickness is formed on a carrier film. FIG. 4 schematically shows a microscopic structure of the raw material mixed powder 14, the first green laminated body 20, the first mixed fired body 21, the first mixed powder 25, the molded body 33, and the ZnO sintered body 34. FIG. Returning to FIG. 1, the thickness of the first green sheet 18 is preferably 5 to 500 μm. If the thickness is less than 5 μm, it becomes difficult to produce a sheet. If the thickness exceeds 500 μm, the effect of crushing aggregates of rare earth element oxide powder cannot be expected, and the ratio of forming the pseudo-solid solution 23 (FIG. 4) is also low. This is because the effect of improving the performance is reduced. Preferably, it is 10-50 micrometers.

  The thickness of the first green sheet 18 in this embodiment is preferably as small as possible from the viewpoint of dispersibility. This is because the contact between the ZnO particles 12 and the rare earth element oxide particles 13 is improved by laminating the layer containing the rare earth element oxide powder and performing pressing or the like, and the contact is made by performing the heat treatment in this state. This is because the pseudo solid solution 23 is easily formed at the interface. Further, the agglomerates 17 of the rare earth element oxide in the raw material mixed powder 14 can be atomized by flattening and firing and pulverizing. Thereby, the dispersibility of the rare earth element oxide in the 1st mixed powder 25 improves, and the effect which improves the composition uniformity of the ZnO sintered compact 34 produced using this is acquired.

<Process for producing first green monolayer or laminate>
As shown in FIG. 1, the first green sheet 18 formed on the carrier film is cut into a predetermined shape and then formed into a first green single layer body 19 or by laminating the green single layer body. One green laminate 20 is formed. The number of stacked layers, Ru 2 to 100 Sodea. When it exceeds 100 layers, there is a problem that lamination becomes difficult. Preferably, it is 5-30 layers. The thickness of the first green laminate 20 is in the range of 10 to 1000 μm. If it is less than 10 μm, there is a problem that it is difficult to maintain the sheet shape during molding and firing. If it exceeds 1000 μm, cracks are generated in the direction perpendicular to the plane of the plate-like hybrid fired body in the grinding process. This is because the effect of fine pulverization cannot be obtained sufficiently. A thickness of 50 to 500 μm is more preferable. The first green laminate 20 may be uniaxially pressed or rolled. The press has an effect of improving the contact between the layers and reducing the thickness.

<Firing step of first green monolayer or laminate>
As shown in FIG. 1, the first green single layer body 19 or the first green laminated body 20 is fired in the atmosphere, an inert gas, a vacuum, or a reducing gas atmosphere. A preferred atmosphere is air. The firing temperature is 1000 ° C. or higher, preferably 1200 to 1400 ° C. The holding time is 1 to 10 hours, preferably 2 to 5 hours. As the sintering proceeds, the thickness of the sheet decreases, and even if the sheet is deformed, there is almost no influence on obtaining the first mixed powder 25 described later. In this way, the first hybrid fired body 21 is produced.

  As shown in FIG. 4, when the first hybrid fired body 21 obtained by firing the first green laminated body 20 obtained from the raw material mixed powder 14 is microscopically observed, Sc, Y, La in the ZnO matrix 22 is observed. , Ce, Pr, Nd, Pm, and Sm, one kind of rare earth element oxide particles selected from the group consisting of ZnO and rare earth element oxide is dispersed to form a pseudo solid solution 23 of ZnO and rare earth element oxide. Usually, the ratio of the rare earth element oxide aggregate 17 present in the raw material mixed powder 14 is small, and when present, the aggregate sintered particles 24 are present in the first hybrid fired body 21. The portion of the rare earth element oxide aggregate 17 exposed on the sheet surface is in contact with the upper or lower ZnO particles, so that more pseudo solid solution is formed than in the case of the green monolayer.

<Crushing step of first hybrid fired body>
As shown in FIG. 1, the first hybrid fired body 21 obtained by the firing is mechanically pulverized to produce a first composite powder 25. As the pulverizer, a jaw crusher, a roll crusher, a hammer crusher, a disc crusher, a stamp mill, a ball mill, a bead mill, a vibration mill, a jet mill, or the like is used. Grind until the average particle size is in the range of 0.1-50 μm. The average particle size is controlled within this range because it is difficult to pulverize to less than 0.1 μm by the mechanical pulverization method, and when it exceeds 50 μm, sintering is performed in the subsequent granulation step and the sintering step after the molding step. This is because the desired sintering density cannot be obtained. A preferable average particle diameter is 0.3 to 5 μm.

  As shown in FIG. 4, the first mixed powder 25 mainly includes composite particles 26 in which rare earth element oxides are incorporated into ZnO particles. In addition, aggregate sintering of rare earth element oxides is performed. There are rare earth element oxide particles 27 formed by pulverizing the particles 24 or ZnO particles 28 formed by pulverizing the ZnO matrix 22. The composite particle 26 produced through the heat treatment step is considered to have a pseudo solid solution 23 of ZnO and rare earth oxide formed at the interface between the ZnO particles and rare earth oxide. In this case, the dispersibility of the rare earth element in the ZnO matrix is improved as compared with the case where the sintered body is formed by simply using the raw material mixed powder 14.

  In addition, the relatively large aggregate 17 of the rare earth element oxide becomes flat when the green sheet is formed. When the diameter of the aggregate 17 of the rare earth element oxide powder in the raw material mixed powder 14 is larger than the doctor blade formation thickness, the aggregate is crushed during green sheet formation. Such flat aggregate sintered particles 24 tend to crack in the direction perpendicular to the surface in the pulverization step, and are relatively easily pulverized to a small diameter. Therefore, a huge aggregate does not remain in the first mixed powder 25. As a result, the dispersibility of the rare earth element oxide in the first mixed powder 25 is improved, and the dispersibility of the rare earth element oxide in the ZnO sintered body 34 produced using this is also improved. On the other hand, when the raw material mixed powder 14 is simply calcined, spherical sintered particles of aggregates of rare earth element oxides are formed as shown in FIG. It is difficult to finely pulverize this compared to the method in this embodiment.

<Granulation process of first mixed powder>
As shown in FIG. 3, the said 1st hybrid powder 25, an organic solvent, and a binder are mixed, and the slurry whose density | concentration is 30-75 mass% is prepared. A preferable concentration is 40 to 65% by mass. The reason why the concentration of the slurry is limited to 30 to 75% by mass is that when the content exceeds 75% by mass, the slurry is non-aqueous, so there is a problem that stable mixed granulation is difficult. This is because a dense ZnO sintered body having the above cannot be obtained. The average particle size of the first composite powder 25 is preferably in the range of 0.3 to 5 μm. The average particle size of the composite powder is defined within the above range because the powder is too fine and agglomerated when the average particle size is less than the lower limit, so that the handling of the powder becomes worse and it is difficult to prepare a high concentration slurry. This is because if the upper limit is exceeded, it is difficult to control the fine structure, and dense pellets cannot be obtained.

As the organic solvent, ethanol or propanol is preferably used, and as the binder, polyethylene glycol, polyvinyl butyral, or the like is preferable. It is preferable that the addition amount of a binder is 0.2-5.0 mass%. The wet mixing of the hybrid powder 25, the binder, and the organic solvent is performed by a wet ball mill or a stirring mill. In the wet ball mill, when ZrO ₂ balls are used, wet mixing is performed for 8 to 24 hours, preferably 20 to 24 hours, using a large number of ZrO ₂ balls having a diameter of 5 to 10 mm. In the stirring mill, wet mixing is performed for 0.5 to 1 hour using a ZrO ₂ ball having a diameter of 1 to 3 mm. Next, the slurry is spray-dried to obtain a granulated powder 32 having an average particle size of 50 to 250 μm, preferably 50 to 200 μm. The spray drying is preferably performed using a spray dryer.

<Molding process>
As shown in FIG. 3, the granulated powder 32 is put in a predetermined mold and molded at a predetermined pressure to produce a molded body 33. As the predetermined mold, a uniaxial pressing device or a cold isostatic pressing device (CIP (Cold Isostatic Press) forming device) is used. A tablet machine, a briquette machine, or the like may be used. In uniaxial pressing apparatus, the granulated powder 32 to 750~2000kg / cm ² (73.5~196.1MPa), preferably uniaxial pressing at a pressure of 1000~1500kg / cm ² (98.1~147.1MPa) and, in CIP molding apparatus, the granulated powder 32 to ^{1000~3000kg / cm 2 (98.0~294.2MPa),} CIP molded under a pressure of preferably 1500~2000kg / cm ² (147.1~196.1MPa) To do. The reason why the pressure is limited to the above range is to increase the density of the molded body 33, prevent deformation after sintering, and eliminate the need for post-processing.

<Sintering process>
As shown in FIG. 3, the compact 33 is sintered at a predetermined temperature to produce a ZnO sintered body (ZnO vapor deposition material) 34. Sintering is carried out at a temperature of 1000 ° C. or higher, preferably 1200 to 1400 ° C. for 1 to 10 hours, preferably 2 to 5 hours in the atmosphere, inert gas, vacuum or reducing gas atmosphere. Thereby, a pellet having a relative density of 90% or more is obtained. The above sintering is performed under atmospheric pressure, but when performing pressure sintering such as hot pressing (HP) sintering or hot isostatic pressing (HIP) sintering, an inert gas, It is preferable to carry out in a vacuum or reducing gas atmosphere at a temperature of 1000 ° C. or higher for 1 to 5 hours. Moreover, it is good also as a plate-shaped sintered compact by uniaxial press. In this way, as shown in FIG. 4, segregation of rare earth elements in the ZnO matrix is suppressed, and a ZnO sintered body (ZnO vapor deposition material) 34 with excellent composition uniformity can be obtained.

<Film formation process>
Using the ZnO sintered body (ZnO vapor deposition material) 34 thus obtained as a vapor deposition source, a ZnO film is formed on the substrate surface by a vacuum film formation method. Examples of the vacuum film forming method for forming the ZnO film include an electron beam evaporation method, a reactive plasma evaporation method, an ion plating method, and a sputtering method.

  When the rare earth additive element is trivalent or tetravalent and is added to the ZnO film, excess carrier electrons are generated relative to the divalent Zn, so that the conductivity of the ZnO film is increased over a wide temperature range. Can be improved.

B. Second Embodiment <Second Slurry Preparation Step>
As shown in FIG. 2, the conditions for preparing the first slurry 11a for forming the first green sheet basically conform to the conditions for preparing the first slurry 11 of the first embodiment. The conditions for preparing the second slurry 11b for forming the second green sheet basically conform to the conditions for preparing the first slurry 11 of Embodiment 1 except that the rare earth element oxide powder is not mixed. That is, the ZnO powder 12 having a purity of 98% or more is dispersed in the dispersion medium 15, and the binder 16 is added to and mixed with the dispersion medium 15 to prepare the second slurry 11b. The types and amounts of the dispersion medium 15 and the binder 16 in the first slurry 11a and the second slurry 11b are the same as those in the first slurry 11 of the first embodiment.

<Second green sheet forming step>
As shown in FIGS. 2 and 5, the second green sheet 18b is formed using the second slurry 11b in the same manner as the formation of the first green sheet. FIG. 5 schematically shows a microscopic structure of the raw material mixed powder 14, the second green laminated body 29, the second mixed fired body 30, the second mixed powder 31, the molded body 33, and the ZnO sintered body 34. FIG. The thickness of the second green sheet 18b is preferably 5 to 500 μm. If the thickness is less than 5 μm, it becomes difficult to produce a sheet, and if it exceeds 500 μm, the effect of fine pulverization cannot be obtained sufficiently. Furthermore, Preferably, it is 10-50 micrometers.

<The manufacturing process of a 2nd green laminated body>
As shown in FIG. 2, the second green sheet 18b formed on the carrier film is cut into a predetermined shape to produce a second green single layer body 19b, and the first green single layer body 19a is laminated thereon. Thus, the second green laminate 29 is produced. It is desirable to alternately stack the second green single layer body 19a and the first green single layer body 19b. The number of stacked layers is 2 to 100 layers. When it exceeds 100 layers, there is a problem that lamination becomes difficult. Preferably, it is 5-30 layers. The thickness of the second green laminate 29 is in the range of 10 to 1000 μm. If the thickness is less than 10 μm, there is a problem that it is difficult to produce a sheet. If the thickness exceeds 1000 μm, cracks are generated in the direction perpendicular to the plane of the plate-like composite fired body and finely pulverized. This is because it cannot be obtained sufficiently. 50-500 micrometers is still more preferable. Further, the second green laminate 29 may be uniaxially pressed or rolled. The press has an effect of improving the contact between the layers and reducing the thickness.

<The firing process of the second green laminate>
As shown in FIGS. 2 and 5, the second hybrid fired body 30 is produced by firing the second green laminate 29. The firing conditions are the same as in the first embodiment.

<Crushing step of second hybrid fired body>
As shown in FIGS. 2 and 5, the second hybrid powder 31 is produced by pulverizing the second hybrid fired body 30. The pulverization conditions are basically the same as those in the first embodiment except that the pulverization is performed until the average particle diameter is in the range of 0.1 to 100 μm.

<Granulation process of second mixed powder>
As shown in FIG. 3, a granulated powder 32 is produced from the second hybrid powder 31. The granulation conditions are the same as in the first embodiment.

<Molding process>
As shown in FIGS. 3 and 5, the granulated powder 32 of the second mixed powder 31 is molded to produce a molded body 33. The molding conditions are the same as in the first embodiment.

<Sintering process>
As shown in FIGS. 3 and 5, the compact 33 of the second composite powder 31 is sintered to produce a ZnO sintered body 34. The sintering conditions are the same as in the first embodiment. In the second practical form, the effect of improving the dispersibility of the rare earth element oxide is obtained as in the case of the first embodiment. In particular, it is effective as a means for effectively dispersing rare earth elements in the case of producing a ZnO sintered body pellet having a very low concentration of rare earth elements.

<Film formation process>
The production of the ZnO film using the ZnO sintered body (ZnO vapor deposition material) 34 produced according to the second actual form as the vapor deposition source is in accordance with the first embodiment.

<Example 1>
First, a first slurry for forming a first green sheet was prepared. Specifically, using an impeller type stirring mixer, a ZnO powder having a purity of 99% and an average particle diameter of 2 μm, and a rare earth element oxide powder of 99% purity and an average particle diameter of 2.5 μm CeO ₂ The powder was dispersed in an organic solvent as a dispersion medium, and polyvinyl alcohol as a binder was added thereto and mixed to prepare a first slurry having a concentration of 30% by mass. The addition amount of the binder was adjusted to 10% by mass when the first slurry after production was 100% by mass. Further, the blending ratio of the ZnO powder and the CeO ₂ powder which is a rare earth element oxide powder is that when the total mass of ZnO and rare earth element oxide in the finally obtained ZnO vapor deposition material is 100 mass%, the rare earth element The Ce element was adjusted so as to contain 5% by mass.

  Next, the prepared first slurry was loaded into a doctor blade device to form a first green sheet having a thickness of 50 μm on the carrier film. Subsequently, a first green single layer body obtained by cutting the first green sheet into a predetermined shape is laminated, and further pressed by uniaxial pressing, whereby a first green having a total thickness of 700 μm consisting of 20 layers. A laminate was formed.

  Next, this first green laminate was fired in the atmosphere at a firing temperature of 1200 ° C. for 3 hours to produce a first hybrid fired body.

  Next, the first hybrid fired body obtained by firing was pulverized using an airflow jet mill to obtain a first composite powder having an average particle size of 0.1 μm.

Next, the first mixed powder obtained above, an organic solvent, and a binder were mixed to prepare a slurry having a concentration of 30% by mass. Ethanol was used as the organic solvent, and polyvinyl alcohol was used as the binder. The amount of binder added was 5% by mass. The wet mixing of the first mixed powder, the binder, and the organic solvent was performed by a wet ball mill. Specifically, wet mixing was performed for 12 hours using a number of ZrO ₂ balls having a diameter of 5 mm. Subsequently, the slurry was spray-dried using a spray dryer to obtain a granulated powder having an average particle size of 250 μm.

Next, this granulated powder was uniaxially pressed at a pressure of 1000 kg / cm ² (98 MPa) using a uniaxial press device (model name: CD type, manufactured by Riken Seiki Co., Ltd.) to produce a compact.

  Finally, the compact was sintered in an air atmosphere at a temperature of 1200 ° C. for 5 hours in an air firing furnace to obtain a ZnO sintered body (ZnO vapor deposition material).

<Example 2>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 1 except that a first mixed powder having an average particle size of 0.7 μm was obtained.

<Example 3>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 1 except that a first mixed powder having an average particle diameter of 3 μm was obtained.

<Example 4>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 1 except that a first mixed powder having an average particle size of 50 μm was obtained.

<Example 5>
As shown in the following Table 1, a ZnO vapor deposition material was formed in the same manner as in Example 3 except that the thickness of the first green sheet was 5 μm and the thickness of the first green laminate was 70 μm. Obtained.

<Example 6>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that the thickness of the first green sheet was 200 μm and the thickness of the first green laminate was 2800 μm.

<Example 7>
As shown in the following Table 1, a ZnO vapor deposition material was formed in the same manner as in Example 3 except that the thickness of the first green sheet was 500 μm and the thickness of the first green laminate was 7000 μm. Obtained.

<Example 8>
As shown in Table 1 below, ZnO was formed in the same manner as in Example 3 except that the first green monolayer was laminated to form a first green laminate having a total of two layers and a thickness of 70 μm. A vapor deposition material was obtained.

<Example 9>
As shown in Table 1 below, ZnO was formed in the same manner as in Example 3 except that the first green monolayer was laminated to form a first green laminate having a total of 100 layers and a thickness of 3500 μm. A vapor deposition material was obtained.

<Example 10>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that Sc ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Example 11>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3, except that Y ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Example 12>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that La ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Example 13>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that Pr ₆ O ₁₁ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Example 14>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that Nd ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Example 15>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that Pm ₂ O ₃ powder was used as the rare earth oxide powder instead of CeO ₂ powder.

<Example 16>
As shown in the following Table 1, a ZnO vapor deposition material was obtained in the same manner as in Example 3 except that Sm ₂ O ₃ powder was used as the rare earth oxide powder instead of CeO ₂ powder.

＜比較例１＞
次の表２に示すように、平均粒径６０μｍの第１混成粉末を得たこと以外は、実施例１と同様に、ＺｎＯ蒸着材を得た。

<Comparative Example 1>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Example 1 except that a first mixed powder having an average particle size of 60 μm was obtained.

<Comparative example 2>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Example 1 except that a first mixed powder having an average particle size of 100 μm was obtained and a granulated powder having an average particle size of 5 mm was obtained. Got.

<Comparative Example 3>
As shown in the following Table 2, a ZnO vapor deposition material was formed in the same manner as in Example 3 except that the thickness of the first green sheet was 600 μm and the thickness of the first green laminate was 8400 μm. Obtained.

<Comparative Example 4>
As shown in the following Table 2, a ZnO vapor deposition material was formed in the same manner as in Example 3 except that the thickness of the first green sheet was 1000 μm and the thickness of the first green laminate was 14000 μm. Obtained.

<Comparative Example 5>
As shown in the following Table 2, a ZnO vapor deposition material was formed in the same manner as in Example 3 except that the thickness of the first green sheet was 3000 μm and the thickness of the first green laminate was 42000 μm. Obtained.

<Comparative Example 6>
As shown in Table 2 below, ZnO was formed in the same manner as in Example 3 except that the first green monolayer was laminated to form a first green laminate having a total of 200 layers and a thickness of 7000 μm. A vapor deposition material was obtained.

<Comparative Example 7>
As shown in Table 2 below, ZnO was formed in the same manner as in Example 3 except that the first green monolayer was laminated to form a first green laminate having a total of 1000 layers and a thickness of 35000 μm. A vapor deposition material was obtained.

<Comparative Example 8>
First, a ZnO powder having a purity of 99% and an average particle diameter of ₂ μm, a CeO ₂ powder having a purity of 99% and an average particle diameter of 2.5 μm as a rare earth element oxide powder, an organic solvent, and a binder The slurry was mixed using the wet ball mill used in No. 1 to prepare a slurry having a concentration of 30% by mass. Ethanol was used as the organic solvent, and polyvinyl alcohol was used as the binder. The amount of binder added was 10% by mass.

  Next, the slurry was spray-dried using a spray dryer to obtain a granulated powder having an average particle size of 250 μm. Next, a molded body is produced from the granulated powder using the same apparatus as in Example 1. Finally, the molded body is sintered under the same conditions as in Example 1 to obtain a ZnO sintered body (ZnO vapor deposition). Material).

<Comparative Example 9>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8 except that Sc ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Comparative Example 10>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8 except that Y ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Comparative Example 11>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8, except that La ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Comparative Example 12>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8, except that Pr ₆ O ₁₁ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Comparative Example 13>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8, except that Nd ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Comparative example 14>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8, except that Pm ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

<Comparative Example 15>
As shown in the following Table 2, a ZnO vapor deposition material was obtained in the same manner as in Comparative Example 8, except that Sm ₂ O ₃ powder was used as the rare earth element oxide powder instead of CeO ₂ powder.

＜比較試験及び評価＞
実施例１〜１６及び比較例１〜１５で得られたＺｎＯ蒸着材を用いて、ガラス基板の上に、電子ビーム蒸着法により、所定の膜厚のＺｎＯ膜を形成した。成膜条件は、到達真空度が１．０×１０^-4Ｐａであり、酸素ガス分圧が１．０×１０^-2Ｐａであり、基板温度が２００℃であり、成膜速度が０．５ｎｍ／秒であった。形成されたＺｎＯ膜について、それぞれ膜厚、透過率及び比抵抗を評価した。これらの結果を次の表３及び表４に示す。

<Comparison test and evaluation>
Using the ZnO vapor deposition materials obtained in Examples 1 to 16 and Comparative Examples 1 to 15, a ZnO film having a predetermined thickness was formed on a glass substrate by an electron beam vapor deposition method. The film formation conditions are as follows: the ultimate vacuum is 1.0 × 10 ⁻⁴ Pa, the oxygen gas partial pressure is 1.0 × 10 ⁻² Pa, the substrate temperature is 200 ° C., and the film formation rate is 0.8. It was 5 nm / second. About the formed ZnO film | membrane, the film thickness, the transmittance | permeability, and the specific resistance were evaluated, respectively. These results are shown in Tables 3 and 4 below.

The film thickness was measured with a Dektak 6M type contact film thickness meter manufactured by ULVAC. The transmittance is measured by using a spectrophotometer U-4000 manufactured by Hitachi, Ltd. as a measuring instrument, and placing the substrate after film formation perpendicular to the measurement light in the visible wavelength range of 380 to 780 nm. did. The specific resistance is determined by a 4-terminal 4-probe method by applying a constant current at a so-called normal temperature at 25 ° C. using a Loresta (HP type, MCP-T410, probe in series 1.5 mm pitch) manufactured by Mitsubishi Chemical Corporation. It was measured. The measurable range of the volume resistance is 1.0 × 10 ^{−6 to} 1.0 × 10 ⁸ Ω · cm.

表１〜表４から明らかなように、実施例１〜９と比較例８とを比較すると、同じ種類の希土類酸化物粉末を添加してＺｎＯ蒸着材を作製したにも拘わらず、実施例１〜９のＺｎＯ蒸着材を用いて成膜された蒸着膜の比抵抗は、比較例８に比べていずれも低く、良好な導電性が得られることが確認された。

As is apparent from Tables 1 to 4, when Examples 1 to 9 and Comparative Example 8 were compared, Example 1 was obtained despite the fact that the same kind of rare earth oxide powder was added to produce a ZnO vapor deposition material. The specific resistance of the vapor deposition film formed using ZnO vapor deposition materials of ˜9 was lower than that of Comparative Example 8, and it was confirmed that good conductivity was obtained.

  Further, when Examples 1 to 9 and Comparative Examples 1 and 2 are compared, in Comparative Examples 1 and 2 in which the average particle diameter of the first composite powder exceeds 50 μm, the sintering does not proceed sufficiently and the desired sintered density is sufficient. Therefore, the specific resistance of the deposited vapor deposited film was higher than those of Examples 1 to 9, and good conductivity was not obtained.

  Further, when Examples 1 to 9 and Comparative Examples 3 to 5 are compared, in Comparative Examples 3 to 5 in which the thickness of the first green sheet exceeds 500 μm, dispersion caused by crushing aggregates of rare earth element oxide powders As a result, the uniformity of the composition in the ZnO vapor deposition material was not sufficiently obtained. For this reason, it was uniform composition and a precise | minute film | membrane was not obtained, the specific resistance of the formed vapor deposition film became high compared with Examples 1-9, and favorable electroconductivity was not obtained.

  Further, when Examples 1 to 9 and Comparative Examples 6 and 7 are compared, in Comparative Examples 6 and 7 in which the number of green sheets stacked exceeds 100, the effect of uniform mixing by pulverization is diminished rather than the number of stacked layers is increased. In this case, since it was difficult to obtain a dense film having a uniform composition, the specific resistance of the deposited film was higher than those of Examples 1 to 9, and good conductivity was not obtained.

Furthermore, when Examples 10 to 16 and Comparative Examples 9 to 15 in which ZnO vapor deposition materials were prepared by adding the same kind of rare earth oxide powder, respectively, although the same kind of rare earth oxide powder was used, First, it was confirmed that the specific resistance of the vapor deposition films formed using the ZnO vapor deposition materials of Examples 10 to 16 was lower than those of Comparative Examples 9 to 15 and good conductivity was obtained. It was. From this, it was confirmed that the present invention is also effective for ZnO vapor deposition materials produced by adding other rare earth oxide powders other than CeO ₂ powder.

11 First Slurry of Embodiment 1 11a First Slurry of Embodiment 2 11b Second Slurry of Embodiment 2 12 ZnO Powder 13 Rare Earth Oxide Powder Containing One Element Selected from Group of Rare Earth Elements 14 ZnO Powder Raw material mixed powder with rare earth element oxide powder 15 Dispersion medium 16 Binder 17 Aggregate of rare earth element oxide powder containing one kind of rare earth element 18 First green sheet 18a of Embodiment 1 First green sheet 18b of Embodiment 2 Implementation Second green sheet in form 2 19 First green monolayer in embodiment 1 19a First green monolayer in embodiment 2 19b Second green monolayer in embodiment 2 20 First green laminate 21 First hybrid Sintered body 22 ZnO matrix 23 Pseudo solid solution of ZnO and rare earth element oxide 24 Rare earth element including one kind of rare earth element Oxide aggregate sintered particles 25 First mixed powder 26 Composite particles in which rare earth element oxide is incorporated into ZnO particles 27 Rare earth element oxide particles made by pulverizing rare earth element oxide aggregate particles 28 ZnO particles formed by pulverizing ZnO matrix 29 Second green laminate 30 Second hybrid fired body 31 Second hybrid powder 32 Granulated powder 33 Molded body 34 ZnO sintered body (ZnO vapor deposition material)

Claims (5)

After forming a granulated powder from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, the granulated powder is molded into a pellet, tablet or plate, and then the molded body. In a method for producing a ZnO vapor deposition material containing 2 to 20% by mass of the rare earth element,
The rare earth oxide powder contains one element selected from the group of rare earth elements,
Mixing the ZnO powder and the rare earth element oxide powder with a dispersion medium and a binder to prepare a first slurry having a concentration of 20 to 90% by mass;
Forming a first green sheet having a thickness of 5 to 500 μm by the doctor blade method using the first slurry;
Firing a first green sheet monolayer or a first green laminate in which a plurality of the first green sheets are laminated to produce a first hybrid fired body;
Crushing the first hybrid fired body to produce a first composite powder having an average particle size of 0.1 to 50 μm;
Look including a step of making the granulated powder by the first hybrid powder,
The method for producing a ZnO vapor deposition material , wherein the number of the first green laminates is 2 to 100, and the thickness of the first green laminate is 10 to 1000 μm . After forming a granulated powder from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, the granulated powder is molded into a pellet, tablet or plate, and then the molded body. In a method for producing a ZnO vapor deposition material containing 2 to 20% by mass of the rare earth element,
The rare earth oxide powder contains one element selected from the group of rare earth elements,
A step of concentration to prepare a first slurry of 20 to 90 wt% of the rare earth element oxide powder and pre-Symbol ZnO powder is mixed with a dispersion medium and a binder,
Forming a first green sheet having a thickness of 5 to 500 μm by the doctor blade method using the first slurry;
Mixing the ZnO powder, the dispersion medium and the binder to prepare a second slurry having a concentration of 20 to 90% by mass;
Forming a second green sheet having a thickness of 5 to 500 μm by the doctor blade method using the second slurry;
Firing a second green laminate obtained by laminating the first green sheet monolayer and the second green sheet monolayer to produce a second hybrid fired body;
Crushing the second hybrid fired body to produce a second composite powder having an average particle size of 0.1 to 100 μm;
Look including a step of making the granulated powder by the second hybrid powder,
The method for producing a ZnO vapor deposition material , wherein the number of stacked second green laminates is 2 to 100, and the thickness of the second green laminate is 10 to 1000 μm .   The method for producing a ZnO vapor deposition material according to claim 2, wherein the thickness of the first green sheet and the thickness of the second green sheet are the same or different.   The method for producing a ZnO vapor deposition material according to claim 1 or 2, wherein one element selected from the group of rare earth elements is Sc, Y, La, Ce, Pr, Nd, Pm, or Sm. A method of forming a ZnO film by a vacuum deposition method ZnO deposition material produced by the method according to any one of claims 1 to 4 as the target material.

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